<template>
  <div class="list" ref="wrapper">
     <div>
        <div class="area">
          <div class="title border-topbottom">您的位置</div>
          <div class="buttom-list">
              <div class="buttom-wrapper">
                <div class="buttom">北京</div>
              </div>
          </div>
        </div>
      <div class="area">
          <div class="title border-topbottom">热门城市</div>
          <div class="buttom-list">
              <div class="buttom-wrapper" v-for="item of hot" :key="item.id">
                <div class="buttom">{{item.name}}</div>
              </div>
          </div>
        </div>
        <!-- 这里是个双重循环，父级的key就等于key就行了 -->
        <div class="area" v-for="(item,key) of cities" :key="key" :ref="key">
            <div class="title border-topbottom">{{key}}</div>
            <div class="item-list">
                <div class="item border-bottom" v-for="innerItem of item" :key="innerItem.id">
                  {{innerItem.name}}
                </div>
           </div>
       </div>
     </div>
  </div>
</template>


<script>
import Bscroll from 'better-scroll'
export default {
  name:"CityList",
  props:{
    hot:Array,
    cities:Object,
    letter:""
  },
  mounted () {
    this.scroll = new Bscroll(this.$refs.wrapper)
  },
  watch : {
    letter () {
      console.log("letter改变了:" + this.letter)
      if(this.letter){
         //为什么要加个取下标0的操作，因为通过循环获取到的ref是一个数组
         const element = this.$refs[this.letter][0]
         this.scroll.scrollToElement(element)
      }
    }
  }
}
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl';
 .border-topbottom
   &:before
      border-color #cccccc
   &:after
      border-color #cccccc
 .border-bottom
   &:before
      border-color #cccccc
 .list
    overflow hidden
    position absolute
    top 1.7rem
    left 0
    right 0
    bottom 0
    .title
        line-height .58rem
        background  #eeeeee
        padding-left .2rem
        color #666
        font-size .26rem
      .buttom-list
        overflow hidden
        padding .1rem .6rem .1rem .1rem
        .buttom-wrapper
            float left
            width 33.3%
            .buttom
              margin .1rem
              padding .1rem 0
              text-align center
              border .02rem solid #cccccc
              border-radius .06rem
      .item-list
          .item
             height .76rem
             line-height .76rem
             padding .2rem
</style>
